1. Technical Field
The present disclosure relates to fan speed control circuits and, more particularly, to a fan speed control circuit capable of regulating the rotation speed of a fan according to feedback from the fan.
2. Description of Related Art
During operation of electronic devices, for example computers, some electronic components, for example CPUs, may generate a lot of heat. Fans in the electronic devices are employed to dissipate heat. Usually, one fan is to dissipate the heat generated by one electronic component. Thus, a number of fans may be mounted in the electronic device to dissipate heat efficiently. Usually, the electronic device employs a number of thermal sensors to detect the temperature of the electronic components. Each sensor is used to detect the temperature of one electronic component. The electronic device generates a PWM signal containing a unique duty cycle corresponding to the detected temperature of one sensor and outputs the PWM signal to the fan monitored by the sensor to control the fan to rotate with a rotation speed. However, depending on the type, manufacturer, and usage time of the fan, the rotation speed may not reach a preset rotation speed when the same PWM signals are sent to the aforementioned fans. Thus, the heat emitted by some electronic components may not be dissipated efficiently, which may cause the electronic device to be burned up. Therefore, it is desired to provide a fan speed control circuit to resolve the above problem.